Aqueous solutions of live vaccines are known to be unstable. The conventional technique to reduce instability is to remove water by lyophilization. Lyophilization, however, is time consuming, energy intensive, and requires the use of very expensive equipment. The major factor controlling the time and expense of lyophilization is the amount of water to be removed. Prior art attempts to reduce lyophilization time and expense by increasing concentration failed due to precipitation of suspension medium ingredients.